The Secret Garden stars Dixie Egerickx as an unhappy, spoiled girl who changes for the better

"I knew the book pretty well - it was my mother's favourite book when she was a kid," the 14-year-old actor says by phone from her home in London.

"I read it when I was seven."

Frances Hodgson Burnett's 1911 novel has been adapted multiple times for film, television and the stage, including a Broadway musical.

The new film, written by Jack Thorne (Harry Potter and the Cursed Child) and directed by Marc Mundsen (whose British TV credits include Utopia and Vanity Fair) is the fourth cinema adaptation of the novel.

In 1947, orphaned Mary Lennox (Egerickx) is sent from India to live with her uncle, Lord Archibald Craven (Colin Firth), a depressed and distant widower, on Misselthwaite Manor, a large Yorkshire estate.

Mary, at the start of the story, is an unhappy and somewhat unpleasant child.

"I guess it's just because her parents didn't love her and in the beginning they die - it's very sad," Egerickx says.

"She's just lonely, you know."

Mary doesn't find her new home very welcoming.

Her uncle is curt and the stern head of the servants, Mrs Medlock (Julie Walters), warns her not to go wandering around the house and tells her to remain in her room.

Naturally, she doesn't obey this edict, exploring the property both inside and out. She comes across a stray dog in the grounds, naming it Jemima.

She also hears strange sounds in the house late at night and eventually discovers their source: her uncle's bedridden son, Colin (Eden Hayhurst).

Mary gradually becomes friendly with one of the servants, Martha (Isis Davis), and her brother Dickon (Amir Wilson), and makes some intriguing discoveries about the manor. One such discovery, of course, being the titular garden, which had been locked up for many years. A robin helps her find the key and it takes her, literally, into a new world, one that changes her life.

Egerickx says the script is "a different adaptation" that makes some changes to the original story - the period is updated, for example, and the ending has been altered - but thinks "we've done a good job bringing out the qualities of the story, its themes and message".

"When she meets the others, she grows as a person so much."

And she's not the only one in whom there are positive changes over the course of the story.

The interiors for The Secret Garden were shot on sets in studios and filming was done in nine different gardens.

"They were combined into the one big one you see in the film."

All the flowers, trees and other vegetation seen in the film were found in the various locations, she says, and she was impressed and a little surprised.

"I didn't realise the UK had that kind of nature."

Very little CGI was used to enhance the lush, heavily vegetated garden spaces except for the magical effects, she says, and the exterior of the grand house was also a mix of the real building and some CGI.

When it comes to the magical elements of the story, she thinks some of what happens might be in her character's head.

"It's kind of mysterious, which is interesting."

At 14, Egerickx is already a seasoned and well-rounded actor. She's worked in theatre, film and television, holding her own alongside such veteran performers as Michael Gambon, Anjelica Huston and Benedict Cumberbatch, but doesn't seen overawed.

In The Secret Garden, she says, "Colin and Julie were both amazing" and quite different from their rather cold characters.

"They were genuinely really lovely."

She's been in quite a few period pieces including The Secret Garden but says it's coincidental, not something she set out to do. In any case, she says, despite the different time periods and settings,"the emotions are the same - the events are different''.

"The characters feel the same whether it's 1900 or 2020."

In The Secret Garden, she found the period costumes she wore to be fun and says they were made to help her cope with the hot weather during the shooting schedule.

"It wasn't too difficult."

Egerickx enjoyed working with Hayhurst and Wilson.

"It was nice to have people my own age on the set," she says.

"I like to think that we became quite good friends."

There are a few doubles for Egerickx credited in the film. Egerickx says this was largely because child actors have limited working hours so some shots, such as those filmed from behind or at a distance, can make use of a double.

"I had one stunt double who was very nice - she did the falling down the wall."

Egerickx was impressed to watch how this kind of action was done by the double.

"I hadn't seen it before," she says.

"It was really amazing."

Meanwhile, she's with her family, undertaking school online and spending time with friends, both virtually and in person.

Egerickx also likes playing the piano - "mostly classical" - and watching television shows such as Black Mirror on Netflix.

She doesn't prefer the screen to the stage when it comes to acting, enjoying their differences - "They're both great fun" - but obviously theatre isn't going to be resuming in a major way for the foreseeable future while COVID-19 is a problem.

But, she says, she's involved with a couple of projects she can't discuss yet.

Asked if she intends to pursue acting as a career, she was unsure.

"I don't really know - I'm enjoying it right now but I'm still very young ... Who knows?" she says.